Gene therapy and drug delivery systems have come a long way since their inception, but target specificity is still a major problem. The challenge, then, is to design a non-viral system with the targeting ability of a virus. One way to accomplish this involves protein-carbohydrate interactions. Lectins are a class of proteins that bind carbohydrates and are found on the surface of cells. Interactions between lectins and carbohydrates are very specific, even to the point of differentiating glucose from galactose. Interestingly, a class of lectins, called galectins specifically bind B-galactosides and are present on the surface of cancer cells. By linking B-galactosides to monodisperse, shape specific biodegradable polymers, it may be possible to specifically target cancer cells. Moreover, these polymers can be filled with a variety of biomaterials or drugs without affecting the biological activity. This system is arguably a first generation "synthetic virus." The beauty in this system is the adaptability in design whereby any protein carbohydrate interaction can be probed and optimized to yield target specific delivery. [unreadable] [unreadable] [unreadable]